1. Field of the Invention
The present invention relates generally to power amplifier circuits, and more particularly, to methods and systems providing and controlling bias voltage to a power amplifier circuit to compensate for the effects of process and temperature induced variations.
2. Description of the Related Art
Portable transmitting devices are becoming more and more common, led first by the popularity of cellular telephones and increasingly by wireless networking products that embody standards such as Bluetooth and 802.11. High volume integrated circuits intended for consumer use promote robust competition and a continuous drive to lower manufacturing costs. Presently, these needs are best met for wireless products by fully integrated transceivers in CMOS technology. Furthermore, architectures favoring simplicity and small size are often more economical than elaborate architectures with higher performance. These principles are applied in the present invention
Unfortunately, transmitters in fully integrated transceiver suffer output power drift due to manufacturing process variations of the amplification circuits (e.g., transistors, resistors, etc.). Transmitters in fully integrated transceivers can also drift due to temperature changes in varying environments and over time as the transmitter generates heat. These variations can cause manufacturing yield loss and/or variable link performance, all undesirable effects. In view of the foregoing, what is needed is a system and method for dynamically compensating for the effects of drift caused by thermal and process variations.